Prepare grill for indirect medium-low heat. Grill ribs, covered, over indirect medium-low heat for 1 hour, turning occasionally. In a saucepan coated with cooking spray, saute onion and garlic over medium heat until tender. In a bowl, combine the cornstarch, syrup, water, soy sauce, molasses, vinegar, ginger and red pepper flakes until blended. Stir into onion mixture. Bring to a boil; cook for 2-3 minutes or until thickened. Add peanut butter; cook for 2 minutes or until peanut butter is melted, stirring constantly. Set aside. Add 10 briquettes to coals. Grill 20-30 minutes longer or until meat is tender, basting ribs with sauce several times. Yield: 6 servings. TEST KITCHEN TIP You can make the sauce the day before you need it; store in the refrigerator.